Molecular Biology Primer Angela Brooks, Raymond Brown, Calvin Chen, Mike Daly, Hoa Dinh, Erinn Hama, Robert Hinman, Julio Ng, Michael Sneddon, Hoa Troung, Jerry Wang, Che Fung Yung Outline: 0. History: Major Events in Molecular Biology 1. What Is Life Made Of?
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Angela Brooks, Raymond Brown, Calvin Chen, Mike Daly, Hoa Dinh, Erinn Hama, Robert Hinman, Julio Ng, Michael Sneddon, Hoa Troung, Jerry Wang, Che Fung Yung
John Craig Venter
Eubacterial (blue green algae)
only one type of membrane--
plasma membrane forms
the boundary of the cell proper
The smallest cells known are bacteria
3x106 protein molecules
1000-2000 polypeptide species.
plants, animals, Protista, and fungi
complex systems of internal membranes forms
organelle and compartments
The volume of the cell is several hundred times larger
5x109 protein molecules
5000-10,000 polypeptide speciesProkaryotes v.s. EukaryotesStructural differences
The genome of E.coli contains amount of t 4X106 base pairs
> 90% of DNA encode protein
Lacks a membrane-bound nucleus.
Circular DNA and supercoiled
Histones are unknown
The genome of yeast cells contains
1.35x107 base pairs
A small fraction of the total DNA encodes protein.
Many repeats of non-coding sequences
All chromosomes are contained in a membrane bound nucleus
DNA is divided between two or more chromosomes
A set of five histones
DNA packaging and gene expression regulationProkaryotic and Eukaryotic CellsChromosomal differences
(A cell is like a car factory)
(DNARNAprotein) The paradigm that DNA directs its transcription to RNA, which is then translated into a protein.
(DNARNA) The process which transfers genetic information from the DNA to the RNA.
(RNAprotein) The process of transforming RNA to protein as specified by the genetic code.
The information for making proteins is stored in DNA. There is a process (transcription and translation) by which DNA is converted to protein. By understanding this process and how it is regulated we can make predictions and models of cells.
Protein Sequence Analysis
1 Physics Ph.D. Student
Nobel PrizeDiscovery of DNA
Rosalind Franklin with X-ray image of DNAWatson & Crick – “…the secret of life”
5’ ATTTAGGCC 3’
3’ TAAATCCGG 5’
Organism Number of base pair number of Chromosomes
Escherichia coli (bacterium) 4x106 1
Saccharomyces cerevisiae (yeast) 1.35x107 17
Drosophila melanogaster(insect) 1.65x108 4
Homo sapiens(human) 2.9x109 23
Zea mays(corn) 5.0x109 10
Lodish et al. Molecular Biology of the Cell (5th ed.). W.H. Freeman & Co., 2003.
DNA and RNA
can pair with
tRNA linear and 3D view:
1 to 178 exons per gene (mean 8.8)
8 bp to 17 kb per exon (mean 145 bp)
average 1 kb – 50 kb per intron
Ribosome in Cytoplasm
*Some other amino acids exist but not in humans.
http://www.sanger.ac.uk/Users/sgj/thesis/node2.html for more information on folding
Normal DNA sequence:
Mutated DNA sequence:
A mutation can cause a trait that enhances the organism’s function:
Mutation in the sickle cell gene provides resistance to malaria.
A mutation can cause a trait that is harmful, sometimes fatal to the organism:
Huntington’s disease, a symptom of a gene mutation, is a degenerative disease of the nervous system.
A mutation can simply cause no difference in the function of the organism.
Campbell, Biology, 5th edition, p. 255